Fluid machinery having a sealing member between stepped spirals

Abstract

A fluid machinery is disclosed which is able to assure a large compression volume without an increase in size and achieve high compressibility by suppressing leakage from sealing, thereby improving the reliability. In the fluid machinery, a second spiral 13 having a spiral inner engaging surface 17 formed to have a stepped shape in section is engaged with a first spiral 15 having an outer engaging surface 21 with a stepped sectional shape which rises upwardly from an outer peripheral side to a central side in a spiral manner, so that sealed spaces 25 are formed to cause reduction in volume of sealed spaces in both radial and height directions from a peripheral side to a central side. A closed spaces 35 having an inclination surface 19 is formed between a stepped surface of the outer engaging surface 21 of the first spiral 15 and a stepped surface of the inner engaging surface 17 of the second spiral 13. A spiral member 37 having a slant surface 39 which engages always with the inclination surfaces 19 is provided in the sealed spaces 35 so as to seal the lower pressure sealed spaces 25 and the higher pressure sealed spaces 25.

What is claimed is: 
     
       1. A fluid machinery comprising: a sealing case;   a first spiral incorporated into said sealing case and having an outer engaging surface having a stepped sectional shape that rises upwardly from an outer peripheral side to a central side in a spiral manner;   a second spiral incorporated into said sealing case and having an inner engaging surface having a stepped sectional shape, said first spiral being rotatable relative to said second spiral;   means for supporting said first spiral and said second spiral to engage said outer engaging surface with said inner engaging surface such that a plurality of sealed spaces are formed therebetween to cause reduction in volume of said sealed spaces from a peripheral side to a central side by virtue of a relative spiral motion between said first spiral and said second spiral; and   a sealing member having a triangular sectional shape provided between said outer engaging surface and said inner engaging surface in a spiral fashion.   
     
     
       2. A fluid machinery as claimed in claim 1, wherein a height of said sealing member increases in an axial direction from a low pressure side to a higher pressure side of said sealed spaces. 
     
     
       3. A fluid machinery as claimed in claim 1, wherein said sealing member has a lateral surface and a vertical surface that are perpendicular to each other. 
     
     
       4. A fluid machinery as claimed in claim 3, wherein said sealing member further has a slant surface contiguous with said lateral and vertical surfaces, said lateral surface, said vertical surface, and said slant surface defining three corners at intersections thereof, wherein at least one of said three corners is chamfered. 
     
     
       5. A fluid machinery as claimed in claim 3, wherein said sealing member further has a slant surface contiguous with said lateral and vertical surfaces, said lateral surface, said vertical surface, and said slant surface defining three corners at intersections thereof, wherein at least one of said three corners is rounded. 
     
     
       6. A fluid machinery as claimed in claim 3, wherein said outer engaging surface and said inner engaging surface each have a spiral horizontal surface that engages directly with each other. 
     
     
       7. A fluid machinery as claimed in claim 3, wherein said outer engaging surface has a spiral horizontal surface and a spiral vertical surface, said lateral surface of said sealing member engaging said spiral horizontal surface, and said vertical surface of said sealing member engaging said spiral vertical surface. 
     
     
       8. A fluid machinery as claimed in claim 7, wherein said inner engaging surface has a spiral slant surface that is slanted relative to said spiral horizontal surface, said sealing member engaging said spiral horizontal surface and said spiral slant surface. 
     
     
       9. A fluid machinery as claimed in claim 8, wherein said inner engaging surface has a spiral vertical surface contiguous with said spiral slant surface via a rounded corner. 
     
     
       10. A fluid machinery as claimed in claim 9, wherein a width of said spiral horizontal surface, an inclination of said spiral slant surface, and a radius of said rounded corner vary in accordance with a spiral position of said stepped surfaces. 
     
     
       11. A fluid machinery as claimed in claim 9, wherein said spiral slant surface, said spiral horizontal surface, and said spiral vertical surface form a substantially triangular sectional shape matching said triangular sectional shape of said sealing member. 
     
     
       12. A fluid machinery as claimed in claim 11, wherein said spiral horizontal surface and said spiral vertical surface intersect at a radial outermost portion of said spiral horizontal surface to form a rounded corner having a radius substantially equal to or slightly larger than a radius of said rounded corner of said inner engaging surface. 
     
     
       13. A fluid machinery as claimed in claim 11, wherein said spiral horizontal surface and said spiral vertical surface intersect to form a rounded corner at a radial innermost portion of said spiral horizontal surface. 
     
     
       14. A fluid machinery as claimed in claim 11, wherein a height of said spiral horizontal surface decreases as said spiral horizontal surface extends radially outwardly. 
     
     
       15. A fluid machinery as claimed in claim 11, wherein said spiral horizontal surface is inclined so that a height of said spiral horizontal surface decreases as said spiral horizontal surface extends radially outwardly.